File permission: assignment

The requirements for E-Learn X are:

- Create capabilities for instructors to manage course readings.
- Create a submissions area that allows for assignment uploads without enabling students to view their peers' submissions.
- Enable media staging for authors while permitting instructors read-only access.
- Confine the use of administrative tools to the system administrators only.

Define User Groups

Create Unix groups corresponding to roles for:

- instructors
- students
- content
- sysadmins

Then assign system users based on their role in the organization.
Directory Structure
An example of a folder structure would be:

text
/opt/elearn/
├── course_materials/
├── submissions/
├── content_staging/
└── admin_tools/

Set Ownership and Permissions

Course Materials
Owner: Instructor(s)
Group: instructors
permissions: Instructors can read/write, students can only access the folder.

chown instructor:instructors /opt/elearn/course_materials
chmod 2754 /opt/elearn/course_materials

(setgid) Ensures group ownership is retained by new files.
(rwx) Owner can read, write,execute.
(r-x) Group can read, execute.
(r--): Others (students) can only read.

Owner: root (or instructor)
Group: students
Permissions: Students may write, but only to files they can access.

chown root:students /opt/elearn/submissions
chmod 1773 /opt/elearn/submissions

(sticky bit): Only file owners can delete their files.
(rwx): Owner can read/write/execute.
(rwx): Group can read/write/execute.
(wx): Others can write/upload, but sticky bit prevents deletion of others’ files.

Content Staging
Owner: content-author
Group: content
Permissions: Content team members can write, and instructors can read.

chown content-author:content /opt/elearn/content_staging
chmod 2750 /opt/elearn/content_staging

(setgid): Requires group inheritance.
(rwx): Owner can read, write, and execute.
(r-x): Group can read and execute.
(---): Others have no access.

Admin Tools
Owner: root
Group: sysadmins
Permissions: Only sysadmins can access.

chown root:sysadmins /opt/elearn/admin_tools
chmod 2770 /opt/elearn/admin_tools

(setgid): Group inheritance.
(rwx): Owner and group have full access.
(---): Others have no access.

Step 4: Special Permissions

SetGID makes sure new files inherit the group of the directory they are placed in.

The sticky bit on submissions prevents file deletion by students unless they were the ones who created the file.